7O FOSSIL TURTLES OF NORTH AMERICA. 
nally a length of about 395 mm., measured in a direct line. The greatest width, 340 mm., 1s 
across the middle of the length of the carapace. Across the axillary notches the width is 315 
mm., and that taken 25 mm. in front of the hinder extremity of the plastron is 306 mm. It will 
be seen therefore that the extremities of the shell are broad. The height of the shell is now 145 
mm. but it was doubtless greater during life. 
Fics. 49 AND 50.—Baéna arenosa. X}. No. 1115 A. M.N. H. 
49. Carapace. Shows the scute areas. Front injured. 
50. Plastron. Shows many of the bones and the scute areas. Front restored. 
The hinder border of the carapace (fig. 49) is rather thin and acute, scallopt as in the 
other species of the genus, and flared somewhat upward. The anterior border is obtuse. All 
the bones are thoroly co-ossified, so that the forms of the neurals 
can not be determined. The surface is uneven, and especially 
Vertebral. | Length. Width. . 5 : 
in the areas occupied by the vertebral scutes there are various 
longitudinal, transverse, and oblique ridges. A slight depression 
- fe occupies the midline of vertebrals 3 and 4. The accompanying 
2 79 . . . a 
3 30 95 table gives the dimensions of the vertebral scutes. In general, 
4 80 go they are wider than long. 
5 75 100 . 
As is not infrequent in the species of the genus, there are, on 
the left side at least, 5 costal plates. The most Anterior is cut 
from the front of the one usually called the first; altho the most anterior vertebral is reduced 
somewhat in width thereby. The portion of the rim of the carapace between the outer border 
of the small anterior costal scute and the posterior vertebral is occupied by 12 marginal scutes. 
The plastron (fg. 50) has an even, but granulated, surface. The anterior lobe is 133 
mm. wide at the base. The bridges are 155 mm. wide. The limits of the mesoplastra are 
indistinctly discernible. They were about 20 mm. wide at the midline and expanded distally 
to about go mm. The hinder lobe is 141 mm. wide at the base and 105 mm. long. It dimin- 
ishes in width slowly backward and the end is truncated. At the ends of the femoro-anal sulci 
the width is yet 113 mm. The lobe lacks about 60 mm. of reaching backward to the hinder 
border of the carapace. 
